Laramie resident John Waggener brushes the snow from the roof of his car in Laramie, Wyo., on Tuesday. / Jeremy Martin AP

by USA TODAY

by USA TODAY

CHEYENNE, Wyo. (AP) - A chilly spring storm was making its way eastward Wednesday after heavy snow and freezing rain prompted hundreds of flight cancellations, stranded motorists and knocked out power to thousands in several Western states.

Officials in South Dakota warned residents to prepare for the worst by staying home and keeping off roads as the system moved through the eastern part of the state.

"We need to hunker down," Sioux Falls Mayor Mike Huether said Tuesday. "This one is going to last a while."

To the south of the wintry weather, severe weather lashed portions of the central Plains overnight, although no tornadoes were reported. Severe storms and tornadoes are possible Wednesday, primarily in the Mississippi Valley and Ohio Valley, according to the Storm Prediction Center.

Meanwhile, as the central USA shivers and the South deals with severe weather, the big cities of the Northeast are seeing near-record warmth, with temperatures more typical of mid-summer. Twelve cities broke or tied record high temperatures on Tuesday, and several more record highs are possible Wednesday, including New York City, Philadelphia, Baltimore and Washington, D.C.

On Tuesday, temperature differences across the Plains were more than 90 degrees. Highs ranged from 12 degrees in Cheyenne, Wyo., to 108 degrees in Laredo, Texas, AccuWeather reported.

The storm crawled eastward Tuesday night from Colorado and Wyoming, with moderate snowfall forecast overnight from the Dakotas to Wisconsin. Nebraska, where strong winds caused a train derailment in the eastern part of the state earlier in the day, also was expecting more snow.

Freezing rain, low temperatures and strong thunderstorms were forecast elsewhere in the Midwest.

Officials in Wyoming and South Dakota closed portions of major highways as blowing snow decreased visibility and freezing rain made roads treacherous. Up to a foot of snow fell in southwestern North Dakota on Monday, causing several vehicle accidents.

"Spring storms are not unusual, but they can be very dangerous," said Greg Fuller, operations director for the Transportation Department.

April snowstorms aren't unusual in Wyoming and the Rocky Mountain West, but the storm comes after a rather tame winter in many areas. The National Weather Service said Cheyenne's high of 12 degrees Tuesday was the coldest on record for April 9. The previous record was 23 degrees set in 1997.

"I'm pretty confident that this particular storm is more widespread and has caused more travel problems and closures than any storm we've had this calendar year certainly," said Bruce Burrows, spokesman for the Wyoming Department of Transportation.

The storm hit California and Arizona on Monday with strong wind and rain, knocking out power to thousands and kicking up a dusty haze in the metropolitan Phoenix area. It moved into Colorado, where two unconfirmed tornadoes were reported near Akron and strong gusts felled trees and power lines. More than six inches of snow fell at Denver International Airport, where hundreds of flights were cancelled and others were delayed.

Wind rolled a trailer home onto its top and a roof blew off a barn, Washington County undersheriff Jon Stivers said. A motorcycle dealership partially collapsed in Pueblo, Colo., where winds gusted to 64 mph.

In Wyoming's Sweetwater County, gusts up to 71 mph damaged a marina at Flaming Gorge Reservoir and broke windows at the Western Wyoming Community College in Rock Springs, according to the National Weather Service.

In parts of the Dakotas, officials cancelled classes and many local governments closed offices. In South Dakota, Secretary of State Jason Gant said more than two dozen cities and school districts informed him they were delaying elections for a week.

AccuWeather reports that the 20 inches of snow that fell Tuesday in Rapid City, S.D., was the snowiest single day on record in the city. The previous record was 18 inches set on April 22, 2001.

Up to a foot of snow fell in southwestern North Dakota, along with freezing rain and sleet. An oil tanker crashed near South Heart, just south of Interstate 94 west of Dickinson, and spilled what authorities called a minimal amount of oil into the ditch.

Interstate 90 was closed between Rapid City and Sioux Falls, and transportation officials will determine which, if any, stretches can reopen.

Weather Service meteorologist Todd Heitkamp in Sioux Falls said that office had reports of ice accumulations from one-quarter of an inch up to nearly half an inch, leading to power outages and widespread tree damage. As much as 10 to 16 inches of snow was expected north and west of the city.

"That's going to add to the weight of the trees, to the power lines," Heitkamp said. "Then we get the wind on top of that and then we get the snow on top of that. You can envision what can possibly occur."

Contributing: Doyle Rice, USA TODAY

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